Various types of liquid crystal devices are known in the art. They include a reflective liquid crystal device which displays an image by reflecting ambient light through a liquid crystal by reflecting means provided in the device, a transmissive type liquid crystal device in which light emitted from a light source provided in the device is passed through a liquid crystal and output to the outside thereby forming an image, and a transflective liquid crystal device capable of switching its displaying mode between reflective and transmissive modes.
Of these liquid crystal devices, reflective liquid crystal devices can operate with very low power consumption because they need no light source. Because of such an advantage, the reflective liquid crystal device is widely used as a display unit in portable devices and other various systems.
In the transflective liquid crystal device, an image is displayed in the transmissive mode using a light source when used in a dark environment. However, when used in a light environment, an image is displayed using ambient light as in the reflective liquid crystal device, and thus it needs low power consumption. Because of such an advantage, the transflective liquid crystal device is widely used as a display unit in portable devices and other various systems. A typical transflective liquid crystal device is, as disclosed in, for example, Japanese Utility Model Publication No. 57-049271, composed of a polarizer, a transflector, and a backlight which are successively disposed on the outer surface, opposite to the viewing side, of a liquid crystal panel. A transflective liquid crystal device with improved brightness is disclosed in Japanese Unexamined Patent Publication No. 8-292413. In this liquid crystal device, a transflector, a polarizer, and a backlight are successively disposed on the outer surface, opposite to the viewing side, of a liquid crystal panel. Because there is no polarizer between the liquid crystal cell and the transflector, an image with improved brightness can be displayed.
With recent advances in portable devices and office automation devices, there is an increasing need for color liquid crystal devices. In many cases, the capability of displaying a color image is also required in systems or devices using a reflective or transflective liquid crystal device. To realize a liquid crystal device having the capability of displaying a color image in the reflective or transflective mode, a color filter having a large number of colored areas of R (red), G (green), and B (blue) is disposed on one of a pair of substrates between which a liquid crystal is disposed. To avoid mixing among different colored areas of the color filter, and to avoid a reduction in the contrast ratio due to struck light-struck (white defects) caused by the spaces between adjacent colored areas, a light shielding film generally called a black mask or a black matrix is disposed in the spaces between adjacent colored areas.